Vapor growth experiments on forsterite, a major silicate mineral in space, were conducted under controlled protoplanetary disk conditions in order to understand its vapor growth kinetics. The growth experiments of forsterite at 1350 K in the presence of hydrogen gas (5 Pa) containing H2O (H2O/H2=0.05) were done at the supersaturation ratio of 15-20, and we found that the condensation coefficient of forsterite, a non-dimension parameter representing kinetic hindrance for vapor growth, is in the range of 0.003-0.006.